"use server";

import type { LoginInput, RegisterInput, AdminLoginInput } from "@/lib/schemas";
import { getDb } from "@/lib/mongodb";
import bcrypt from 'bcryptjs';
import { cookies, headers as nextHeaders } from 'next/headers';
import { redirect } from 'next/navigation';
import type { User } from "@/lib/types";
import { revalidatePath } from "next/cache";
import { ObjectId } from 'mongodb'; // Import ObjectId

const ADMIN_EMAIL = 'ogdavidcyril@gmail.com';
const REFERRAL_COIN_BONUS_FOR_REFERRER = 10;
const REFERRAL_WELCOME_BONUS_FOR_NEW_USER = 5;
const ADMIN_INITIAL_COINS = 999999;
const MAX_ACCOUNTS_PER_IP = 1; // Limit for accounts per IP


export async function loginUser(data: LoginInput) {
  try {
    const db = await getDb();
    const usersCollection = db.collection<User>("users");

    const user = await usersCollection.findOne({ email: data.email });

    if (!user) {
      return { success: false, message: "Invalid email or password." };
    }

    const isPasswordValid = await bcrypt.compare(data.password, user.passwordHash);

    if (!isPasswordValid) {
      return { success: false, message: "Invalid email or password." };
    }

    cookies().set('loggedInUserId', user._id.toString(), {
      path: '/',
      httpOnly: true,
      secure: process.env.NODE_ENV === 'production',
      maxAge: 60 * 60 * 24 * 7,
      sameSite: 'lax',
    });
    redirect('/dashboard');

  } catch (error) {
    if (typeof error === 'object' && error !== null && 'message' in error && typeof error.message === 'string' && error.message.includes('NEXT_REDIRECT')) {
      throw error;
    }
    console.error("Login error:", error);
    return { success: false, message: "An unexpected error occurred during login." };
  }
}

function getClientIp(): string | null {
  const headersList = nextHeaders();
  const xForwardedFor = headersList.get('x-forwarded-for');
  if (xForwardedFor) {
    return xForwardedFor.split(',')[0].trim();
  }
  const xRealIp = headersList.get('x-real-ip');
  if (xRealIp) {
    return xRealIp.trim();
  }
  // Fallback, might not be available or accurate depending on deployment
  // For Firebase App Hosting, 'x-forwarded-for' should be populated by the load balancer.
  // Other headers like `fastly-client-ip` or `true-client-ip` might be available too.
  return headersList.get('remoteAddress') || null; // 'remoteAddress' is not standard here
}


export async function registerUser(data: RegisterInput) {
  try {
    const db = await getDb();
    const usersCollection = db.collection<User>("users");

    const existingUser = await usersCollection.findOne({ email: data.email });
    if (existingUser) {
      return { success: false, message: "This email is already registered." };
    }

    const clientIp = getClientIp();
    if (clientIp) {
      const existingAccountsWithIp = await usersCollection.countDocuments({ registrationIp: clientIp });
      if (existingAccountsWithIp >= MAX_ACCOUNTS_PER_IP) {
        return { success: false, message: "Registration limit reached for this network. Please try again later or contact support if you believe this is an error." };
      }
    } else {
      console.warn("Could not determine client IP address for registration. IP-based limit will not be applied for this user.");
      // Decide if you want to block registration if IP is not found, or proceed with a warning.
      // For now, we'll proceed but log it.
    }

    const passwordHash = await bcrypt.hash(data.password, 10);

    let roleToAssign: 'user' | 'admin' = 'user';
    let initialCoins = 0;

    if (data.email === ADMIN_EMAIL) {
      roleToAssign = 'admin';
      initialCoins = ADMIN_INITIAL_COINS;
    }

    const newUserObjectIdString = new ObjectId().toString();

    const namePart = data.name.substring(0, 5).toLowerCase().replace(/[^a-z0-9]/g, '');
    const randomPart = newUserObjectIdString.slice(-6);
    const referralCode = `${namePart}${randomPart}`;

    const newUserDocument: User = {
      _id: newUserObjectIdString,
      name: data.name,
      email: data.email,
      passwordHash,
      role: roleToAssign,
      coins: initialCoins,
      lastCoinClaim: null,
      referralCode: referralCode,
      referredBy: null,
      createdAt: new Date(),
      registrationIp: clientIp || undefined, // Store IP if available
    };

    if (data.referralCode) {
      const referrer = await usersCollection.findOne({ referralCode: data.referralCode });
      if (referrer) {
        await usersCollection.updateOne(
          { _id: referrer._id },
          { $inc: { coins: REFERRAL_COIN_BONUS_FOR_REFERRER } }
        );
        newUserDocument.referredBy = referrer._id.toString();
        if (data.email !== ADMIN_EMAIL) {
            newUserDocument.coins += REFERRAL_WELCOME_BONUS_FOR_NEW_USER;
        }
      } else {
        console.log(`Referral code ${data.referralCode} not found or invalid.`);
      }
    }

    const result = await usersCollection.insertOne(newUserDocument);

    if (!result.insertedId) {
        return { success: false, message: "Failed to register user." };
    }

    return { success: true, message: "Registration successful! You can now log in." };
  } catch (error) {
    console.error("Registration error:", error);
    return { success: false, message: "An unexpected error occurred during registration." };
  }
}


export async function adminLoginUser(data: AdminLoginInput) {
  try {
    const db = await getDb();
    const usersCollection = db.collection<User>("users");

    const user = await usersCollection.findOne({ email: data.email });

    if (!user) {
      console.log(`Admin login attempt: User not found for email ${data.email}`);
      return { success: false, message: "Invalid email or password." };
    }

    const isPasswordValid = await bcrypt.compare(data.password, user.passwordHash);

    if (!isPasswordValid) {
      console.log(`Admin login attempt: Invalid password for email ${data.email}`);
      return { success: false, message: "Invalid email or password." };
    }
    console.log(`Admin login attempt: Password valid for ${data.email}`);

    // For the designated admin email, ensure role is 'admin' and coins are set correctly.
    if (user.email === ADMIN_EMAIL) {
      const updates: Partial<Pick<User, 'role' | 'coins'>> = {};
      let needsDatabaseUpdate = false;

      if (user.role !== 'admin') {
        updates.role = 'admin';
        needsDatabaseUpdate = true;
        console.log(`Admin login: ${user.email} role is ${user.role}, needs update to admin.`);
      }
      if (user.coins !== ADMIN_INITIAL_COINS) {
        updates.coins = ADMIN_INITIAL_COINS;
        needsDatabaseUpdate = true;
        console.log(`Admin login: ${user.email} coins are ${user.coins}, needs update to ${ADMIN_INITIAL_COINS}.`);
      }

      if (needsDatabaseUpdate) {
        await usersCollection.updateOne({ _id: user._id }, { $set: updates });
        console.log(`Admin user ${user.email} DB record updated/ensured: role to ${updates.role || user.role}, coins to ${updates.coins !== undefined ? updates.coins : user.coins}`);
        // Update the local user object to reflect changes immediately
        if (updates.role) user.role = updates.role;
        if (updates.coins !== undefined) user.coins = updates.coins;
      } else {
        console.log(`Admin login: ${user.email} already has correct admin role and coins.`);
      }
    } else if (user.role !== 'admin') {
        // If it's not the ADMIN_EMAIL, then they must already be an admin to use this login route.
        console.log(`Admin login attempt: ${data.email} is not the ADMIN_EMAIL and does not have admin role.`);
        return { success: false, message: "Access denied. Not an admin account." };
    }

    console.log(`Admin login: Setting cookie for user ${user._id} (${user.email}) with role ${user.role}`);
    cookies().set('loggedInUserId', user._id.toString(), {
      path: '/',
      httpOnly: true,
      secure: process.env.NODE_ENV === 'production',
      maxAge: 60 * 60 * 24 * 7, // 1 week
      sameSite: 'lax',
    });

    revalidatePath('/admin/dashboard');
    console.log(`Admin login: Revalidated /admin/dashboard, redirecting...`);
    redirect('/admin/dashboard');

  } catch (error) {
     if (typeof error === 'object' && error !== null && 'message' in error && typeof error.message === 'string' && error.message.includes('NEXT_REDIRECT')) {
      throw error;
    }
    console.error("Admin login error:", error);
    return { success: false, message: "An unexpected error occurred during admin login." };
  }
}

export async function logoutUser() {
  try {
    cookies().delete('loggedInUserId');
    revalidatePath('/');
    redirect('/login');
  } catch (error) {
    if (typeof error === 'object' && error !== null && 'message' in error && typeof error.message === 'string' && error.message.includes('NEXT_REDIRECT')) {
      throw error;
    }
    console.error("Logout error:", error);
    return { success: false, message: "Logout failed due to an unexpected error." };
  }
}

export interface LoggedInUser {
  _id: string;
  name: string;
  email: string;
  role: 'user' | 'admin';
  coins: number;
  lastCoinClaim: Date | null;
  referralCode: string;
  createdAt: Date;
  referredUsersCount: number;
  referralCoinsEarned: number;
  // registrationIp is not typically exposed in LoggedInUser for privacy, but available in DB User type.
}

export async function getLoggedInUser(): Promise<LoggedInUser | null> {
  try {
    const userIdCookie = cookies().get('loggedInUserId');
    if (!userIdCookie?.value) {
      return null;
    }
    const userIdString = userIdCookie.value;

    const db = await getDb();
    const usersCollection = db.collection<User>('users');
    const user = await usersCollection.findOne({ _id: userIdString });

    if (user) {
      // Ensure admin user has correct role and coins, self-correct if needed
      if (user.email === ADMIN_EMAIL) {
        let adminNeedsUpdate = false;
        const adminUpdates: Partial<Pick<User, 'role' | 'coins'>> = {};
        if (user.role !== 'admin') {
          adminUpdates.role = 'admin';
          adminNeedsUpdate = true;
        }
        if (user.coins !== ADMIN_INITIAL_COINS) {
          adminUpdates.coins = ADMIN_INITIAL_COINS;
          adminNeedsUpdate = true;
        }
        if (adminNeedsUpdate) {
          await usersCollection.updateOne({ _id: user._id }, { $set: adminUpdates });
          if(adminUpdates.role) user.role = adminUpdates.role;
          if(adminUpdates.coins !== undefined ) user.coins = adminUpdates.coins;
          console.log(`Self-correction in getLoggedInUser for ${user.email}: role to ${user.role}, coins to ${user.coins}`);
        }
      }

      const referredUsersCount = await usersCollection.countDocuments({ referredBy: user._id });
      const referralCoinsEarned = referredUsersCount * REFERRAL_COIN_BONUS_FOR_REFERRER;

      return {
        _id: user._id,
        name: user.name,
        email: user.email,
        role: user.role || 'user',
        coins: user.coins || 0,
        lastCoinClaim: user.lastCoinClaim ? new Date(user.lastCoinClaim) : null,
        referralCode: user.referralCode || 'N/A',
        createdAt: user.createdAt ? new Date(user.createdAt) : new Date(0),
        referredUsersCount: referredUsersCount,
        referralCoinsEarned: referralCoinsEarned,
      };
    }
    console.log(`getLoggedInUser: No user found for ID ${userIdString}`);
    return null;
  } catch (error) {
    console.error("Error fetching logged in user:", error);
    return null;
  }
}